PETALUMA — Passenger seats for Sonoma and Marin counties' commuter rail line failed a crash-worthiness test last week, but officials said Wednesday it was in no way a setback for the system.

The manufacturer and Sonoma-Marin Area Rail Transit District said the seats will be redesigned in a month and that it will not delay delivery of the first two-car set by the end of this year.

"Whatever needs to be done will be corrected," said Gene Germaine, director of business development for Kustom Seating Unlimited of Bellwood, Ill. "As it stands, there is no delay in the normal process in developing the product and testing it and having it signed off and meeting the requirements."

Lisa Cobb, SMART's vehicle and systems manager, said at a SMART meeting Wednesday in Petaluma that such failures are common because the car design is new and has new components.

"This is not unusual because it is hard test," she said.

During testing the seat frames failed under the G-forces equivalent to a 25 mph crash, Cobb said. In one case, the structure of a seat bent back. In another, a seat cushion did not remain in place.

"We will continue to work with the car builder as they go through the safety qualification testing before the cars get here, and after the cars arrive in order to ensure safe service for our riders," Cobb said.

The $360 million first phase of the project — with service beginning in 2015 or 2016 — will connect San Rafael and Santa Rosa.

In Marin, the line will offer stops at Atherton Avenue, Hamilton Field, the Marin Civic Center and downtown San Rafael. An adjacent pedestrian and bicycle path will be part of the project. The second phase would extend service through the Cal Park Hill Tunnel to a station near the Larkspur Ferry Terminal, although funding has not been identified for that work.